This application claims the priority of German Application No. 103 12 224.9-14 filed Mar. 19, 2003, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method of producing components subjected to flow and components made by said method. Preferred embodiments of the invention related to methods of producing disc-shaped or ring-shaped components subjected to flow, in particular of rotor discs having integral blading for turbomachines, by milling and finish machining subsequent to the milling, the component being milled out of a workpiece, and a finish machining medium flowing through the component for the finish machining after the milling.
During the production of components subjected to flow, in particular during the production of rotor discs or rings with integrated blading, as a rule, the procedure according to the prior art is that the component subjected to flow is milled out of a workpiece and the component produced by milling is subsequently subjected to finish machining.
U.S. Pat. No. 6,077,002 discloses a milling method for producing rotor discs having integrated blading. In the milling method shown there, a milling cutter is moved relative to the workpiece to be machined in such a way that milling ridges which appear are oriented approximately parallel to the aerodynamic direction of flow through the component during operation, e.g. during subsequent use in a gas turbine.
European Patent Document EP 1 128 933 B1 (corresponding Canadian Patent 2,343,694) discloses an arrangement for the finish machining of rotor discs having integral blading. To this end, a finish machining medium flows through the component produced by milling. The prior art according to European Patent Document EP 1 128 933 B1 relates to “chemically assisted barrelling”.
Starting therefrom, a problem underlying the present invention is to provide a novel method of producing rotationally symmetrical components.
This problem is solved in that the method mentioned at the beginning for producing components subjected to flow is developed by providing a method of producing disc-shaped or ring-shaped components subjected to flow, in particular of rotor discs having integral blading for turbomachines, by milling and finish machining subsequent to the milling, the component being milled out of a workpiece, and a finish machining medium flowing through the component for the finish machining after the milling, wherein the component is milled out of the workpiece in such a way that milling ridges which are produced extend approximately perpendicularly to a direction of flow of the finish machining medium at the component.
The method according to the invention for producing disc-shaped or ring-shaped components subjected to flow relates, inter alia, to the production of rotor discs having integral blading, i.e. of “blisks” (bladed disks), for all turbomachines, in particular gas turbines.
The rotor discs are produced by milling and by finish machining downstream of the milling, the component being milled out of a workpiece, and a finish machining medium flowing through the component for the fine machining after the milling.
According to preferred embodiments of the invention, the component is milled out of the workpiece in such a way that milling ridges which are produced run or extend approximately perpendicularly to the direction of flow of the finish machining medium at the component. The direction of flow of the finish machining medium at the component or the rotor disc therefore runs transversely, preferably perpendicularly, to the milling ridges appearing during the upstream milling. As a result, the effectiveness of the finish machining is markedly improved. Manual treatment of the rotor disc and in particular of the rotor blades can be dispensed with. This results in cost advantages and time advantages during the production of rotor discs. The direction of flow of the finish machining medium at the component corresponds approximately to the aerodynamic direction of flow through the component during operation.
According to an advantageous development of the invention, plunge milling is used for the milling, the main feed direction of a milling cutter during the plunge milling running in the direction of its cutter axis. Plunge milling, also called piercing, ensures stable cutter guidance during the milling.
Abrasive flow machining or chemically assisted barrelling is preferably used for the finish machining. Manual treatment of the component can be dispensed with.
A combination of abrasive flow machining or chemically assisted barrelling as finish machining method and plunge milling, the milling ridges produced during plunge milling running approximately perpendicularly to the direction of flow of the finish machining medium at the component, is especially advantageous and effective.
Preferred developments of the invention are set forth in the claims and the following description.
Exemplary embodiments of the invention, without being restricted thereto, are explained in more detail with reference to the drawing.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.